MONDAY, Aug. 16 (HealthDay News) -- Bariatric weight-loss surgery in obese people with type 2 diabetes can have an unexpected, yet positive side effect -- nearly 3 out of 4 patients in one study were able to stop taking their insulin and other diabetes medications within six months of surgery.

In a study of more than 2,200 U.S. adults, Johns Hopkins University researchers found that two years after the operation, almost 85% were off diabetes medications as a result of improved blood glucose levels.

And although the surgery is expensive, the researchers found that because of the reduction in type 2 diabetes medications and related health care costs, the surgery appeared to be a cost-effective option, reducing health care costs by more than $6,000 annually.

"We've got a new epidemic in the world replacing smoking -- it's obesity. And, the number one health consequence of obesity is type 2 diabetes. Now, we have an effective surgical intervention for two major health problems," said the study's lead author, Dr. Martin Makary, a surgeon and associate professor of surgery and of public health at Johns Hopkins University School of Medicine.

But, he cautioned, the surgery isn't a quick fix solution and it isn't for everyone. "This surgery is for the right candidates -- to qualify for bariatric surgery you have to have a body mass index greater than 30. And, it's something that needs to be considered when all other interventions have failed."

Results of the study were published in the August issue of the Archives of Surgery.

Diabetes can be a debilitating and expensive disease. A recent report from the Agency for Healthcare Research and Quality found that the United States spends $83 billion each year on hospital costs related to diabetes. The same report estimates that nearly 8% of the U.S. population has diabetes.

Several years ago, surgeons realized that when they performed weight-loss surgery that reduces the stomach's capacity, some people were able to go off insulin or other diabetes medications within days of surgery. The current study was designed to look at how the surgery correlates with a reduction in diabetes medication use, and the costs of the procedure versus the continued need for diabetes medications and other related health care expenses.

Makary and his colleagues examined 2,235 adults with type 2 diabetes from seven different states who had undergone bariatric weight-loss surgery over a four-year period between January 1, 2002 and December 31, 2005. The risk of death from this surgery is 0.3%, according to Makary.

Of the participants, 85.8% were taking at least one diabetes medication before surgery, with an average of 4.4 medications per patient. The researchers found that within six months of surgery, 1,669 (74.7%) of the surgical patients were able to stop taking their diabetes medications. After one year, 80.6% were off diabetes medications and at two years, 84.5% were no longer taking them.

Even many of those who previously needed to take insulin, which indicates more advanced disease, were able to stop taking it.

The average cost of surgery for this type of procedure is nearly $30,000, according to the study. The average annual health care cost for each person with type 2 diabetes was estimated to be about $6,376 in the two years preceding the surgery. Total annual health care costs increased by nearly 10% in the year following the surgery, but dropped by 34.2% by year two and by 70.5% by year three, when health care costs declined by nearly $4,500 annually.

"This is not just a surgery that addresses obesity, but it also eliminates the need for diabetes medications in the vast majority. There are enormous implications for health care utilization and policies. This surgery is not only in the patient's best health interest, but will also result in a significant reduction in resources," said Makary.

Because the surgery causes such a rapid reduction in the need for diabetes medication, Makary said it's not just the weight loss that's causing the change in diabetes, but likely a shift in certain hormones in the body.

Dr. Joel Zonszein, director of the Clinical Diabetes Center at Montefiore Medical Center in New York City, agreed that a hormonal change is likely the cause. "While we don't understand the exact mechanism, it's believed to be changes in the incretin system," he said. The incretin system produces gastrointestinal hormones.

"The effect of bariatric surgery is very dramatic, and leads to a very quick resolution of type 2 diabetes," he said, but added that the current study is only done on a limited population -- those who are very obese.

Makary said that there is ongoing research in performing this surgery in people who aren't obese, but have type 2 diabetes. However, he said that he doesn't recommend the procedure for those who wouldn't currently be recommended for surgery, because the risk-to-benefit ratio wouldn't be as favorable.

Like all surgeries, bariatric surgery carries its own set of possible risks, including such early complications as bleeding, infection and leaks from sites where body tissues are sewn or stapled together, and blood clots in the legs that may travel to the heart, according to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases. The institute also notes that later complications may include malnutrition (particularly in people who don't take their prescribed vitamins and minerals), hernias, and a tendency in about one in 10 people to regain much of the weight they lost as a result of the procedure.

SOURCES: Martin Makary, M.D., surgeon, and associate professor of surgery and of public health, Johns Hopkins University School of Medicine, Baltimore; Joel Zonszein, M.D., professor of clinical medicine, and director, Clinical Diabetes Center, Montefiore Medical Center and Albert Einstein College of Medicine, New York City; August 2010, Archives of Surgery; August 2010, Statistical Brief 93, Healthcare Cost and Utilization Project (HCUP), U.S. Agency for Healthcare Research and Quality, Rockville, Md.